1. Field Of The Invention
The invention generally relates to insulated backpacks or insulated containers insertable into backpacks, bike packs, duffle bags and the like.
2. Description Of The Prior Art
The prior art includes many backpacks or backpacklike containers which have insulating properties. Chief among the prior art patents is U.S. Pat. No. 4,673,117, issued to J. D. Calton, which shows a backpack cooler including an insulated foam core covered on the outside with a cloth sheet. The foam core has a separate, tight-fitting lid. A separate insulated container insertable into a separate compartment of a backpack is seen in U.S. Pat. No. 4,706,856, issued to J. M. Jocober. The principal object of both Calton and Jocober is to keep carried items either warmer or cooler than the ambient conditions surrounding the backpack user.
Other insulated chests or containers carried on a person's back are seen in U.S. Pat. No. 4,449,378, issued to K. Thorpe and U.S. Pat. No. 3,980,216, issued to G. G. Nye. A separate top is used to seal the container in Nye. The patent to Thorpe shows multiple compartments having specialized uses, many of which are insulated to keep food or liquid either warm or cold.
Numerous other prior art patents show portable carriers which insulate food or liquid but which are not necessarily carried on the back. Other prior art shows portable containers, principally for liquids, having varying degrees of insulation, which are designed to be carried on a person's back, though not in association with a standard backpack.
All of the backpacks having insulation, or the containers which are insulated and used in association with backpacks in the prior art, are specifically designed and made to go with a particular backback. Heretofore, no thermal insert for a backpack has been available which is used with any one of several commercially-available backpacks. Backpacks are widely used for carrying anything from school books to camping supplies. Allowing the flexibility to convert an existing conventional packpack into an insulated backpack has not, heretofore, been available.